A string is valid if all characters of the string appear the same number of times. It is also valid if we can remove just 1 character in the string, and the remaining characters will occur the same number of times. Given a string s, determine if it is valid. If so, return true, otherwise return false. For example, if s=abc, it is a valid string because frequencies are {a:1,b:1,c:1} . So is s=abcc because we can remove one c and have 1 of each character in the remaining string. If s=abccc however, the string is not valid as we can only remove 1 occurrence of c. That would leave character frequencies of {a:1,b:1,c:2}.